Just by changing the tube, it should not change the setting of the switch.
Did it work ok before it was cut?
If it has, you should be fine by just replacing it.
The air should not affect it. If it is to far of a run, the switch may bounce. on and off, on and off. If it does this, the tube may need to be shortened, or move the switch close to the tank.
The switch always works better when it is close to the tank.